Machines to separate differently sized particles, such as aggregate shakers, sifters, or vibrating screeners are well known in the art, particularly for construction, industrial, and other related applications. These machines include vibrating decks which receive wire screens for separating larger sized particles from smaller sized particles, by shaking loads of aggregate, rocks, dirt, and related material through one or more screens. The screens may have openings arranged to sort particle sizes from a fraction of an inch to several inches, as needed. A single shaker may include a plurality of generally vertically stacked screens for simultaneously separating multiple sizes from the same load of material. Due to the harsh conditions under which the screens are used, the screens have to be replaced regularly. Traditional screens generally comprise two sets of wires woven perpendicularly together.
To increase the lifespan and decrease the required maintenance of wire screens, self-cleaning screens are also now commonly used. The self-cleaning screens generally include wires which extend in a single longitudinal direction, with a support means to hold the wires in alignment. Thus, each wire can vibrate at its own frequency and the wires can separate from each other, so that rocks or debris will be shaken loose from the screen and the screen will not easily blind or clog. That is, due to the individually vibrating wires, self-cleaning screens do not experience the same level of build-up or blinding as do traditional woven screens.
The support means for some self-cleaning screens comprise small groups of perpendicularly woven wires, which act to support the screen at intervals along the screen. However, the metal-on-metal contact caused by the woven wires increases wear on the screen at the woven sections and decreases the lifespan of the screens. To increase the flexibility and lifespan of the screens, other self-cleaning screens may include a strip of a polymer material formed about and around the groups of perpendicularly woven wires. The polymer support strips are generally made by placing two pre-formed polymer bars or strips, one above the wires and one below, and then welding them together by heating the bars. Although this fuses the two bars together, support members made in this way still suffer from delamination or general weakness at the interface where the two bars are welded together. Even when polymer support strips are used, the perpendicularly woven wires are often required to first also be included, so that the woven wires hold the longitudinal wires of the screen in the final configuration while the polymer strips are formed. Screens which include both a polymer strip and perpendicularly woven wires require additional time, material, and cost to manufacture than traditional screens. Without the pre-weaving, some other means would be required to at least temporarily hold the wires in the screen's final configuration.
As a result, self-cleaning screens are desired that include the benefits of polymer support members, but not the shortcomings of woven perpendicular wires, and which take less time, material, and cost to manufacture than screens which include both woven wires and polymer support strips. Thus, what is, needed a method an apparatus for creating a self-cleaning screen which includes polymer support means and which does not require pre-weaving of other wires, and does not require pre-formed polymer bars or strips.